1. Field of the Invention
This invention relates to motorcycle engines of the internal combustion type having a plurality of cylinders, and, more particularly, to an intake manifold for such an internal combustion engine using only a single carburetor.
2. Description of the Prior Art
Relatively small, air cooled internal combustion engines used to provide motive power for motorcycles typically have a carburetor for each cylinder in multi-cylinder engines. There are obvious disadvantages involved with having a plurality of carburetors, such as excessive fuel consumption, adjustment in balancing of multiple carburetors, and costs involved in both the purchase of multiple carburetors and the maintenance on the multiple carburetors. One of the limitations involved in providing only a single carburetor for multiple cylinders, such as is done with multi-cylinder internal combustion engines used to provide motive power for automobiles, is the space limitation of providing a manifold which is able to allow for the transmission of an adequate fuel and air mixture from a single carburetor to each of the plurality of cylinders.
Due to the space limitations, the carburetors typically used for motorcycle applications are side draft carburetors rather than the downdraft carburetor such as used in automotive applications. There are many downdraft carburetors available from a variety of manufacturing sources, and the ability to adapt a downdraft carburetor to multi-cylinder motorcycle engines is accordingly highly desirable. To take a stock downdraft carburetor, rework the jets, and fit such modified carburetor to a motorcycle engine is highly desirable from several standpoints, such as efficiency, cost, and maintenance, since a downdraft carburetor is less expensive than a sidedraft carburetor, is more efficient in use, and there are obviously less problems of maintenance, balancing, and tuning of a single carburetor, as opposed to multiple carburetors for a single engine.